Not vaccinating children leads them open to contracting potentially deadly diseases, as well as putting others in danger.

There is a link displayed on the billboard that leads to a website that is full of misleading claims that vaccines are harmful and unnecessary.

"Vaccines contain multiple synthetic chemicals that should never be injected into the body and are part of the reason we have skyrocketing chronic health issues that have somehow become the new 'normal' in our society," the website reads.

Mr Cook was quick to shut down these claims and call for the removal of the billboards.

"It is a common misconception that many of these infections are not serious; however, they can all cause serious illnesses and in some cases death, even among children who are otherwise fit and healthy," he said in a statement.

"The World Health Organisation considers immunisation to be the most effective medical intervention we have to prevent deaths and reduce disease in our communities."